Razor-blade knife



April 7, 1925. 1,532,499

B. T. KAVANAUGH RAZOR BLADE KNIFE Filed April 5, 1922 Patented Apr. Li 19 25.

- one!) STATES niinronn r. KAVANAUGH, or cnrceco, mnmoi RAZOR-BLADE KNIFE.

Application flied April 3, 1922. Serial No. 549,216.

To all whom it may concern:

Be it known that I,.BE1 F0RD T. KAVA- NAUGH, a citizen of the United States, re siding at Chicago, in the county of Cook and btate of Illinois, have invented a certain new and useful Improvement in Razor- Blade Knives, of which the following 1s a full, clear, concise, and exact descript on, reference being had to the accompanylng drawings, forming a part of this speclfication.

My invention relates to a razor blade knife, of the class designed to utilize new or old safety razor blades for obtaining a renewable cutting edge of great sharpness.

Qne of the principal objects of the invention is to provide a device of the above class in which both edges of a double edged razor blade are exposed so that either can be used without the necessity of removing and reversing the blade.

A further object of the invention 1s to provide an -arrangement for adjustably mounting the blade, whereby the angle f the blade can be turned or shifted relatlve to the shank or handle portion of the device. By virtue. of this ability to turn the blade to any preferred angle the device 1s particularly adapted to use for shaving, or for cutting where a greater depth of blade is desired, or in otherwise inaccessible locations.

A further object is to provide a construction wherein the razor blade is movable into and out of its protecting sheath by a longitudinal slidin motion.

A further 0 ject is to provide anarrangement of stra for grasping the median portionof the b ade in such a manner that the device will be adjustable for receiving different Widths and lengths ofblades.

A further object is to provide a safety razor guard which is quickly-attachable to the device for use in shaving.

In the accompanying drawing illustrating a prefered embodiment:

Figure 1 is a sectional view through one form of my device illustrating the razor blade extended;

Fig. 2 is an elevational view of the device closed up;

Fig. 3 is a sectional view through the blade and strap;

Fig. 4 is a transverse sectional view on the plane of the line 4-4. of Figure 1;

Fig. 5 is an end view of the guide member which supports and guides the sheath;

Flg. 6 is a vertical sectional view of'the same;

Fig. 7 is a plan view of the device closed up, a portion of the device being broken away to illustrate thetaper at the ends of the sheath arms;

8 is a view similar to, Fig. 4 of a modification, with a single-edge razor blade held in position.

Fig. 9 is a view similar to Figure 1 of another modification; and

Fig. 10 illustrate s'the latter with-a singleedge razor blade inserted shows the safety the blade.

The device of my invention comprises primarily a strap or blade engaging 1118111- er 12, a guide or clamping block 13 to which the strap 12 is secured, and a slida ble sheath 14: adapted to be slid over or drawn back from the edges of the blade I; or vice versa. The strap 12 consists of a looped strip of metal adapted to extend out around the end of the blade I) and'to engage only the medial ortion of the blade, thereby leaving both edges of the blade exposed. The strap 12 is comparatively thin in section and the corners thereof are preferably beveled so that the strap presents a negligible projection on each side of the razor blade. Thetwo free ends of the strap are reduced and threaded as indicated at 15, the threads on these reduced ends matchingto form a cylindrical screw over which threads the knurled nut 16. Instead of forming the strap as a loop, it can be formed as a solid rod or bar threaded at one end therein, and also razor guard 1n positlon on and having a slot extending the greater 9 portion'of its length for receiving the blade. This strap, in either form, braces the blade laterally and prevents the blade from buckling when placed under compression.

The threaded end of the strap is adapted to engage in the clamping block or bridge 13. This bridge or clampin member extends beyond the edges of the b adeb and is suificiently thicker than the thickness of the blade to accommodate the arms 18 of the sheath 14. The clamping block or guide member 13 has a central aperture 19 of polygonal outline, and to either side there of has elongated guide apertures 21 to receive the arms 18 of the sheath 14. Intermediate the wide ortion of the strap and the reduced threa ed portions 15 there are formed shank portions 17 having flattened sides which snugly fit within the polygonal aperture .19 and hold the strap 12 against turning relative to the bridge or clamping member 13.

The two arms 18 of the sheath 14 are joined at the rear by a connecting portion or portions 23. The two arms 18 are of U- shaped cross section (Fig. 4), deslgned to snugly embrace each edge of the blade I) on either side of the strap 12. The inner edges of each sheath arm bear along the corresponding edges of the strap 12 on each side of the blade, these edges of the strap 12 serving to guide the sheath over the blade with the assistance of the guiding apertures 21 or walls thereof, so that the inner part or face of each sheath arm is held 1n spaced relation to the razor edges to prevent dulling of the same. The sheath 14 1s preferably constructed as a sheet metal stamping; one expedient method being to flatten out a section of tubing, leaving the sldes spaced sufiiciently to snuggly engage over the razor blade, and slotting out one end of the blank to provide the U-shaped outline shown. 7

The knife is closed by pushing the sheath 14 forward through the bridge or guide member 13 or vice versa, so that the extending arms of the sheath overlie and protect the edges of the blade I). The abutment of the thumb screw 16 against the transverse end portions 23 limits the telescopic motion of the sheath over the blade. When the sheath is drawn out to uncover the blade, its outward motion is limited by small spurs or flanges 24 which are struck up or out from the ends of the sheath arms and engage against the end, or in recesses in the end, of the guide member 13. -These spurs or lugs 24 are preferably struck out from the end of the sheath after the same has been inserted in the guide member 13. The outward motion of the sheath 14 is preferably so limited that the forward corners of the sheath arms remain embracing the sides of the blade when the sheath is withdrawn as far as it will go. Thisprevents any possibility of the end of the blade I) getting out of registry with the comparatively narrow slot in each sheath arm 18.

It will be noted that the very considerable tension which can be imposed upon the strap 12 through the thumb nut 16 rigidly clamps the blade against the guide member 13. The blade bears against the central hub portion 26 of this guide member, the forward face of this hub portion having slots 26' curved to correspond to the curvature characteristic of the type of blade illustrated at 5. Similarly, the loop at the outer end of the strap 12 is curved to correspond to the curvature at this end of the blade and it is understood that these parts are formed according to the shape of the blade. By loosening the thumb nut 16 and relieving the tension on the strap 12, it will be observed that the blade can be rotated or shifted angularly to raise or lower the heel or toe of either edge of the blade relative to the handle portion, which portion is defined by the sheath 14. These positlons are partly indicated in dotted l nes, and upon giving the blade the deslredangular adjustment, it can be clamped in this position by tightening the thumb nut 16 and drawing the blade back against the hub portion 26 through the medium of the strap 12. By virtue of this angular adjustabil ty of the blade, the device can be convenlently used for shaving, the upward inclination of the handle portion 14 relative t the edge of the blade enabling all portlons of the blade edge to be brought into contact with the face in the same manner as wlth the old style straight razor. The inclination of the blade in this manner prevents the guide member 13 or handle portion '14 from interfering with the working edge of the blade. Extending either end of the blade in this manner, also enables the knife to cut deeper in work on comparatively thick materials, and enables the point of the blade to be extended into spots which would be otherwise inaccessible.

iRigidity between the blade 5 and the guide member 13 is assured by reason of the tension which can be imposed upon the blade through the thumb nut 16, and by reason of the slots 26 in the face of the hub portion 26. The required rigidity or tightness of fit between the guide member 13 and the sheath or handle portion 14 may be obtained by various methods. For example, at the ends of the sheath arms 18, the side walls 18' can be separated on a diverging taper, as indicated at 28. The two side walls 18 are of course compressible towards each other, and this gives the required resiliency to the taper. By forcing the guide member 13 out over this taper, an operation easily accomplished in drawing the sheath out of the guide member, the sheath and guide member .ean be securely locked together so that considerable pressure can be exerted through the sheath 14, serving as a handle, without play between the sheath and guide member. This rigidity is further augmented by the comparatively long guiding surfaces at the outer ends of the guide openings 21 and along the inner ends of these guide openings over the hub portion 26.

A further method of securely binding the guide member 13 to the sheath, is by separating the two sheath arms divergingly as indicated in Fig. 2. en the sheath is withdrawn from the rear of the guide member, these sheath arms will be compressed together against their natural resiliency, so

- that the required pressure can be obtained trative of another method, the guide member 13 could be formed with punched depressions 31, as shown in Fig. 10, to engage in corresponding depressions 32, 1n the ends of the sheath arms.

In Figs. 8 and 10 I have also illustrated a washer or disk 35 rotatably mounted on the threaded end of the strap and having opposite cam tails or projections 35' adapted to engage in pairs of slots or recesses 36 in the inner edges of the sheath arms 18. When the sheath is withdrawn the rotation of this member spreads the sheath arms outwardly against the guide apertures by the camming action ofthe tails 35. The provision of the two pairs of slots 36 at opposite ends of the sheath permits the guide and blade to be locked to the sheath when extended or closed. Either one or acombinationof these methods may be employed for firmly clamping the guide member 13 to the sheath when the sheath is extended.

As shown in Fig. 8, by the simple expe' dient of widening the spacing in one of the sheath arms 18, the device can be adapted to receive interchangeably either the double edge type of blade shown at b, or the single edge type of blade, shown at I) having a rim or bar 33 extending along the other edge thereof. The widened sheath arm is capable of engaging over the upper edge of the blade 6 or the bar 33 on the blade I).

By making the sheath 14 and the strap 12 slightly longer, as shown in Fig. 9, the range of the device can be extended to also include comparatively long razor blades 72 (of the t e illustrated by the Durham-Duplex blad eg. In this form, the thread 15 is extended up a considerable distance on the two halves of the strap 12, so that by screwing the thumb nut 16 forwardly, the strap can be drawn back sufliciently far to also i receive blades of the type Z) and b. To accommodate the projecting end of the strap when the same is threaded backwardly in this manner, the endof the sheath has an aperture or recess 34 to perniit the strap to extend beyond the end ofthc. sheath. Fig. 10 illustrates a single edge blade I)" mounted in such an embodiment. served that in all of these forms the periphery of the thumb nut 16 projects sufficiently beyond the sides of the sheath 14 to be readily accessible for convenient manipulaof the foregoing types,

It will be ob tion by the fingers. Any suitable ring or connecting device 38 may be swiveled to one end of the sheath, or the sheath may have a suitable eye 37, as for convenient connection {3% the end of a Watch chain, key ring or the I also contemplate providing a safety guard 40 adapted for convenient applicatlon over one edge of the blade to convert the same into a safety razor. This guard preferably comprises a flattened loop of metal having teeth or serrations 39. The connected ends of the loop engage over the ends of the blade, which may be of either and the guard can be clamped to this blade by compressing it against the end of the guide member 13 or the end of the sheath 14 by tension imposed through the thumb nut 16 and the end of the blade.

While I have shown anddescribed in detail herein a device embodying the features of my invention, itis to be of course understood that the details' of construction and arrangement of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim: 4

1. In a device of the class described, the combination of means for grasping the blade including a guide, and a sheath moving through said guide adapted to cover or uncover both edges of the blade.

2. In a-device of the class described, the combination of means for grasping the median portion of the blade, and a sheath guided by said means and movable longitudinally of said blade to cover or expose both edges ofsaid blade, said sheath comprisin two U-shaped edge portions separated y intermediate slots, saidedge portions embracing the edges of said blade.

3. In combination, means for grasping the blade, said means engaging around the outer end of the blade, a guide member to which said. grasping means is secured, both edges of the blade being exposed and free to permit angular adjustment of the blade at either side, and a protecting member guided by said guide member for shifting movement over or away from said blade.

4. In combination, blade grasping means including a tension strap engaging around the outer edge of the blade, said grasping means adapted to clamp the blade laterally and endwise, a guide member to which said grasping means is secured, and a sheath having guided engagement with said guiding member and adapted for longitudinal movement for uncovering and covering the edge of said blade.

5. In combination, means for grasping the median portion of the blade, a guide member to which said grasping means is secured, means permitting adjustment of said and grasping means relative to said guide member, said guide member comprising guide surfaces, and a sheath movable along said guide surfaces substantially longitudinally of said blade.

,6. In combination, means adapted to engage the median portion of the blade on each side thereof, said means also engaging around the outer end of the blade a guiding member, said first-named means being operable to secure the blade to said guiding member, and a sheath guided by said member for motion longitudinally of said blade.

7. In combination, means for grasping the median portion of the blade on each side thereof, a guide member to which said means is secured, said member having guiding apertures therein, and a sheath guided in said apertures and movable longitudinally of said blade for covering both edges thereof.

8. In combination, a clamping member adapted to engage over the end of the blade, a guide member cooperating therewith, said clamping member being movable longitudinaliy of said guide member to clamp the blade to said guide member, and a slidable sheath shiftable longitudinally of said guide member and said blade.

9. In combination, a [guide member, a clamping member adapted to engage over one end of the blade and draw the other end of said blade against said guide member, said clamping member being releasable for interchanging blades, and a protecting member supported by said guide member and movable to cover or uncover the edge of said blade.

10. In combination, a guide member, a clamping member engageable over one end of the blade, tensioning means cooperating with said clamping means for drawing the other end of said blade against said guide member, said guide member having guiding apertures therein, and a sheath aided in said apertures and shifted longitu inally of said blade for covering both edges thereof.

11. In combination, a guide member, a strap engageable over one end of the blade and supported in said guide member, screw threaded means for imposing a tension on said strap and thereby drawing the other end of said blade against said guide member, said guide member having guiding apertures therein, and a U-shaped sheath guided in said apertures and movable longitudinally of said blade for protecting both edges thereof.

12. In combination, a guide member, a strap engaging over one end of the blade and extending along the median portion thereof to leave both edges of said blade exposed, said strap having a threaded portion extending through an aperturein said guide member, a nut engaging over said threaded portion for drawing the other end of said blade against said guide member, said guide member havin guiding apertures disposed in the plane 0 the blade, and a protecting sheath slidable in said apertures longitudinally of the blade and adapted to cover both edges of said blade.

13. In combination, a guide member, means for detachably securing the blade to said guide member, a sheath movable longitudinally of said guide member, and means for preventing said guide member from moving beyond the end of said sheath When sald sheath is moved to expose said blade.

14. In combination, a guide member, means for detachably securing a razor blade to said guide member, a sheath guided by said member and movable longitudinally of said blade for protecting the same, and detent projections on the sheath for preventlng said guide member from being drawn out beyond the end of said sheath when the latter is withdrawn from its proteeting position over the blade.

15. In combination, a guidemember, means for securing the blade to said guide member, a sheath guided by said member and movable longitudinally of said blade, and detent means brought into cooperative relation between said guide member and said sheath when said sheath is drawn outward to expose said blade.

16. In combination, a guide member, means for clamping the razor blade to said guide member, a sheath guided by said member and shiftable to cover and uncover the edge of said blade, and means for cre- I ating a compression between said guide member and said sheath when said sheath is drawn outward to uncover said blade.

17. In combination, a guide member, a

strap engageable over one end of the blade,

and supported by said guide member, means for placing the strap under tension to draw said blade against said guide member, said guide member having guiding apertures therein, a sheath movable through sald apertures and adapted to cover and uncover both edges of said blade, and a safety razor guard adaptedto be disposed in juxtaposition to the edge of said blade.

18. In a device of the class described, the combination of means for grasping the median portion of a double edged razor blade laterally, said means also embracing the outer end of said blade, and a handle portion with slots open at one end and.

combination of blade grasping means and a handle portion having opposite U-shaped parts adapted to telescope over said blade, said grasping means engaging around the end of said blade and exerting a pressure thereon, whereby said blade can be adjusted relative to said handle portion.

20. In a device of the class described, the combination of blade holding means, a protecting shield associated with said means, said blade holding means engaging over the end of the blade and holding the same in position by exerting a longitudinal pressure on the blade, and means for relieving said longitudinal pressure to permit angular adjustment of said blade.

21. Means for grasping the median portion of the blade, a handle portion adapted to be moved telescopically over said blade for protecting both edges thereof, and means co-operating with said grasping means to enable diflerent portions of said blade to be engaged, whereby said blade can be shifted angularly relative to said handle portion.

22. In a razor blade knife of the class described, the combination of -means for clamping a blade, and a sheath moving through and opening in said clamping means and adapted to cover and uncover both edges of the blade during telescopic and extension movement of the parts, one relative to the other, said clamping means having a central part ada ted to engage the blade.

23. In a evice of the class described, the combination of means for grasping the blade, and a sheath moving through an opening in said grasping means and adapted to cover or uncover both edges of the blade, said grasping means including a guide mounted on the sheath and the. sheath being 40 movable through the guide.

24. In a device of the clas-s'described, the combination of blade clamping means, and a handle portion adapted to telescope over said blade, said clamping means engaging around the end of the blade and the opposite faces thereof, and means to clamp the blade. in different angularly adjusted ositions with the opposite edges thereo exposed.

25. In a device of the class described, the combination of means for grasping the blade and a sheath movable longitudlnally through said grasping means over the edge of the blade, the grasping means adapting 65 the blade tobe angularly adjusted at one end of the sheath.

26. In a device of the class described, the combination of means for grasping the blade, and a sheath having an open end and lateral slots therein and movable longitudinally over said blade to expose or cover both edges of said blade, the grasping means adapting the blade to be angularly adjusted therein at either or both sides at the open end of the sheath and in engagement with the latter.

In witness whereof, I hereunto subscribe my name this 28th day of March, 1922.

BEDFORD T. KAVANAUGH. 

